Convert config loading to TOML, refactor appropriately

This PR refactors SimplePush to use TOML config loading, changes the existing portions to a new Application based init system, and config loading for each section similar to heka's.

A variety of Go idiom portions were also cleaned up, the logger was factored into an extensible logger with a uniform interface.

Fixes Issue #35.

Awaiting r+ from @jrconlin, @rafrombrc.
Redirects are a client provided feature. They allow us to instruct a given client to go to a given server (Clients fall back to the well known address) These were not fully implemented due to some delays from client dev, however could be very useful in the future. 

I'll add some documentation to this code for future reference and use.